open-feature · beeme1mr · Apr 25, 2025 · Feb 21, 2025 · Feb 22, 2025 · Feb 22, 2025
@@ -15,5 +15,6 @@
     "providers/ofrep": "0.1.5",
     "providers/prefab": "0.0.2",
     "tests/flagd": "1.4.1",
-    "providers/go-feature-flag-in-process": "0.1.0"
+    "providers/go-feature-flag-in-process": "0.1.0",
+    "providers/multi-provider": "0.0.3"
 }
@@ -0,0 +1,10 @@
+.PHONY: generate test
+GOPATH_LOC = ${GOPATH}
+
+generate:
+	go generate ./...
+	go mod download
+	mockgen -source=${GOPATH}/pkg/mod/github.com/open-feature/go-sdk@v1.13.1/openfeature/provider.go -package=mocks -destination=./internal/mocks/provider_mock.go
+
+test:
+	go test ./...
@@ -0,0 +1,84 @@
+OpenFeature Multi-Provider
+------------
+
+The Multi-Provider allows you to use multiple underlying providers as sources of flag data for the OpenFeature server SDK. 
+When a flag is being evaluated, the Multi-Provider will consult each underlying provider it is managing in order to 
+determine the final result. Different evaluation strategies can be defined to control which providers get evaluated and 
+which result is used.
+
+The Multi-Provider is a powerful tool for performing migrations between flag providers, or combining multiple providers 
+into a single feature flagging interface. For example:
+
+- **Migration**: When migrating between two providers, you can run both in parallel under a unified flagging interface. 
+As flags are added to the new provider, the Multi-Provider will automatically find and return them, falling back to the old provider 
+if the new provider does not have
+- **Multiple Data Sources**: The Multi-Provider allows you to seamlessly combine many sources of flagging data, such as 
+environment variables, local files, database values and SaaS hosted feature management systems.
+
+# Installation
+
+```sh
+go get github.com/open-feature/go-sdk-contrib/providers/multi-provider
+go get github.com/open-feature/go-sdk
+```
+
+# Usage
+
+```go
+import (
+	"github.com/open-feature/go-sdk/openfeature"
+	mp "github.com/open-feature/go-sdk-contrib/providers/multi-provider"
+)
+
+providers := make(mp.ProviderMap)
+providers["providerA"] = providerA
+providers["providerB"] = providerB
+provider, err := mp.NewMultiProvider(providers, mp.StrategyFirstMatch, WithLogger(myLogger))
+openfeature.SetProvider(provider)
+```
+
+# Options
+
+- `WithTimeout` - the duration is used for the total timeout across parallel operations. If none is set it will default 
+to 5 seconds. This is not supported for `FirstMatch` yet, which executes sequentially
+- `WithFallbackProvider` - Used for setting a fallback provider for the `Comparison` strategy
+- `WithLogger` - Provides slog support
+
+# Strategies
+
+There are multiple strategies that can be used to determine the result returned to the caller. A strategy must be set at
+initialization time.
+
+There are 3 strategies available currently:
+
+- _First Match_
+- _First Success_
+- _Comparison_
+
+## First Match Strategy
+
+The first match strategy works by **sequentially**  calling each provider in the order that they are provided to the mutli-provider.
+The first provider that returns a result. It will try calling the next provider whenever it encounters a `FLAG_NOT_FOUND`
+error. However, if a provider returns an error other than `FLAG_NOT_FOUND` the provider will stop and return the default
+value along with setting the error details if a detailed request is issued. (allow changing this behavior?)
+
+## First Success Strategy
+
+The First Success strategy works by calling each provider in **parallel**. The first provider that returns a response
+with no errors is returned and all other calls are cancelled. If no provider provides a successful result the default
+value will be returned to the caller.
+
+## Comparison
+
+The Comparison strategy works by calling each provider in **parallel**. All results are collected from each provider and
+then the resolved results are compared to each other. If they all agree then that value is returned. If not and a fallback
+provider is specified then the fallback will be executed. If no fallback is configured then the default value will be 
+returned. If a provider returns `FLAG_NOT_FOUND` that is not included in the comparison. If all providers
+return not found then the default value is returned. Finally, if any provider returns an error other than `FLAG_NOT_FOUND`
+the evaluation immediately stops and that error result is returned. This strategy does NOT support `ObjectEvaluation`
+
+# Not Yet Implemented
+
+- Hooks support
+- Event support
+- Full slog support
@@ -0,0 +1,18 @@
+module github.com/open-feature/go-sdk-contrib/providers/multi-provider
+
+go 1.23.0
+
+require (
+	github.com/open-feature/go-sdk v1.13.1
+	github.com/stretchr/testify v1.9.0
+	go.uber.org/mock v0.5.1
+	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842
+	golang.org/x/sync v0.7.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
@@ -0,0 +1,24 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
+github.com/go-logr/logr v1.4.2/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/golang/mock v1.6.0 h1:ErTB+efbowRARo13NNdxyJji2egdxLGQhRaY+DUumQc=
+github.com/golang/mock v1.6.0/go.mod h1:p6yTPP+5HYm5mzsMV8JkE6ZKdX+/wYM6Hr+LicevLPs=
+github.com/open-feature/go-sdk v1.13.1 h1:RJbS70eyi7Jd3Zm5bFnaahNKNDXn+RAVnctpGu+uPis=
+github.com/open-feature/go-sdk v1.13.1/go.mod h1:O8r4mhgeRIsjJ0ZBXlnE0BtbT/79W44gQceR7K8KYgo=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+go.uber.org/mock v0.5.1 h1:ASgazW/qBmR+A32MYFDB6E2POoTgOwT509VP0CT/fjs=
+go.uber.org/mock v0.5.1/go.mod h1:ge71pBPLYDk7QIi1LupWxdAykm7KIEFchiOqd6z7qMM=
+golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842 h1:vr/HnozRka3pE4EsMEg1lgkXJkTFJCVUX+S/ZT6wYzM=
+golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842/go.mod h1:XtvwrStGgqGPLc4cjQfWqZHG1YFdYs6swckp8vpsjnc=
+golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
+golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/text v0.19.0 h1:kTxAhCbGbxhK0IwgSKiMO5awPoDQ0RpfiVYBfK860YM=
+golang.org/x/text v0.19.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=